{-# LANGUAGE OverloadedStrings #-}
{- |
   Module      : Text.Pandoc.Readers.BibTeX
   Copyright   : Copyright (C) 2020-2021 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Parses BibTeX or BibLaTeX bibliographies into a Pandoc document
with empty body and `references` and `nocite` fields
in the metadata.  A wildcard `nocite` is used so that
if the document is rendered in another format, the
entire bibliography will be printed.
-}
module Text.Pandoc.Readers.BibTeX
  ( readBibTeX
  , readBibLaTeX
  )
where

import Text.Pandoc.Options
import Text.Pandoc.Definition
import Text.Pandoc.Builder (setMeta, cite, str)
import Citeproc (Lang(..), parseLang)
import Citeproc.Locale (getLocale)
import Text.Pandoc.Error (PandocError(..))
import Text.Pandoc.Class (PandocMonad, lookupEnv)
import Text.Pandoc.Citeproc.BibTeX as BibTeX
import Text.Pandoc.Citeproc.MetaValue (referenceToMetaValue)
import Text.Pandoc.Sources (ToSources(..))
import Control.Monad.Except (throwError)

-- | Read BibTeX from an input string and return a Pandoc document.
-- The document will have only metadata, with an empty body.
-- The metadata will contain a `references` field with the
-- bibliography entries, and a `nocite` field with the wildcard `[@*]`.
readBibTeX :: (PandocMonad m, ToSources a)
           => ReaderOptions -> a -> m Pandoc
readBibTeX :: ReaderOptions -> a -> m Pandoc
readBibTeX = Variant -> ReaderOptions -> a -> m Pandoc
forall (m :: * -> *) a.
(PandocMonad m, ToSources a) =>
Variant -> ReaderOptions -> a -> m Pandoc
readBibTeX' Variant
BibTeX.Bibtex

-- | Read BibLaTeX from an input string and return a Pandoc document.
-- The document will have only metadata, with an empty body.
-- The metadata will contain a `references` field with the
-- bibliography entries, and a `nocite` field with the wildcard `[@*]`.
readBibLaTeX :: (PandocMonad m, ToSources a)
             => ReaderOptions -> a -> m Pandoc
readBibLaTeX :: ReaderOptions -> a -> m Pandoc
readBibLaTeX = Variant -> ReaderOptions -> a -> m Pandoc
forall (m :: * -> *) a.
(PandocMonad m, ToSources a) =>
Variant -> ReaderOptions -> a -> m Pandoc
readBibTeX' Variant
BibTeX.Biblatex

readBibTeX' :: (PandocMonad m, ToSources a)
            => Variant -> ReaderOptions -> a -> m Pandoc
readBibTeX' :: Variant -> ReaderOptions -> a -> m Pandoc
readBibTeX' Variant
variant ReaderOptions
_opts a
t = do
  Maybe Text
mblangEnv <- Text -> m (Maybe Text)
forall (m :: * -> *). PandocMonad m => Text -> m (Maybe Text)
lookupEnv Text
"LANG"
  let defaultLang :: Lang
defaultLang = Text
-> Maybe Text
-> Maybe Text
-> [Text]
-> [(Text, [(Text, Text)])]
-> [Text]
-> Lang
Lang Text
"en" Maybe Text
forall a. Maybe a
Nothing (Text -> Maybe Text
forall a. a -> Maybe a
Just Text
"US") [] [] []
  let lang :: Lang
lang = case Maybe Text
mblangEnv of
              Maybe Text
Nothing  -> Lang
defaultLang
              Just Text
l   -> (String -> Lang) -> (Lang -> Lang) -> Either String Lang -> Lang
forall a c b. (a -> c) -> (b -> c) -> Either a b -> c
either (Lang -> String -> Lang
forall a b. a -> b -> a
const Lang
defaultLang) Lang -> Lang
forall a. a -> a
id (Either String Lang -> Lang) -> Either String Lang -> Lang
forall a b. (a -> b) -> a -> b
$ Text -> Either String Lang
parseLang Text
l
  Locale
locale <- case Lang -> Either CiteprocError Locale
getLocale Lang
lang of
               Left CiteprocError
e  ->
                 case Lang -> Either CiteprocError Locale
getLocale (Text
-> Maybe Text
-> Maybe Text
-> [Text]
-> [(Text, [(Text, Text)])]
-> [Text]
-> Lang
Lang Text
"en" Maybe Text
forall a. Maybe a
Nothing (Text -> Maybe Text
forall a. a -> Maybe a
Just Text
"US") [] [] []) of
                   Right Locale
l -> Locale -> m Locale
forall (m :: * -> *) a. Monad m => a -> m a
return Locale
l
                   Left CiteprocError
_  -> PandocError -> m Locale
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (PandocError -> m Locale) -> PandocError -> m Locale
forall a b. (a -> b) -> a -> b
$ CiteprocError -> PandocError
PandocCiteprocError CiteprocError
e
               Right Locale
l -> Locale -> m Locale
forall (m :: * -> *) a. Monad m => a -> m a
return Locale
l
  case Variant
-> Locale
-> (Text -> Bool)
-> a
-> Either ParseError [Reference Inlines]
forall a.
ToSources a =>
Variant
-> Locale
-> (Text -> Bool)
-> a
-> Either ParseError [Reference Inlines]
BibTeX.readBibtexString Variant
variant Locale
locale (Bool -> Text -> Bool
forall a b. a -> b -> a
const Bool
True) a
t of
    Left ParseError
e -> PandocError -> m Pandoc
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (PandocError -> m Pandoc) -> PandocError -> m Pandoc
forall a b. (a -> b) -> a -> b
$ Sources -> ParseError -> PandocError
PandocParsecError (a -> Sources
forall a. ToSources a => a -> Sources
toSources a
t) ParseError
e
    Right [Reference Inlines]
refs -> Pandoc -> m Pandoc
forall (m :: * -> *) a. Monad m => a -> m a
return (Pandoc -> m Pandoc) -> Pandoc -> m Pandoc
forall a b. (a -> b) -> a -> b
$ Text -> [MetaValue] -> Pandoc -> Pandoc
forall a b. (HasMeta a, ToMetaValue b) => Text -> b -> a -> a
setMeta Text
"references"
                              ((Reference Inlines -> MetaValue)
-> [Reference Inlines] -> [MetaValue]
forall a b. (a -> b) -> [a] -> [b]
map Reference Inlines -> MetaValue
referenceToMetaValue [Reference Inlines]
refs)
                         (Pandoc -> Pandoc) -> (Pandoc -> Pandoc) -> Pandoc -> Pandoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Text -> Inlines -> Pandoc -> Pandoc
forall a b. (HasMeta a, ToMetaValue b) => Text -> b -> a -> a
setMeta Text
"nocite"
                            ([Citation] -> Inlines -> Inlines
cite [Citation :: Text
-> [Inline] -> [Inline] -> CitationMode -> Int -> Int -> Citation
Citation {citationId :: Text
citationId = Text
"*"
                                            , citationPrefix :: [Inline]
citationPrefix = []
                                            , citationSuffix :: [Inline]
citationSuffix = []
                                            , citationMode :: CitationMode
citationMode = CitationMode
NormalCitation
                                            , citationNoteNum :: Int
citationNoteNum = Int
0
                                            , citationHash :: Int
citationHash = Int
0}]
                                            (Text -> Inlines
str Text
"[@*]"))
                        (Pandoc -> Pandoc) -> Pandoc -> Pandoc
forall a b. (a -> b) -> a -> b
$ Meta -> [Block] -> Pandoc
Pandoc Meta
nullMeta []